The technology described herein relates generally to turbomachinery, particularly to gas turbine engines, and more particularly, to a gas turbine engine guide vane assembly.
At least one known gas turbine engine assembly includes a fan assembly that is mounted upstream from a core gas turbine engine. During operation, a portion of the airflow discharged from the fan assembly is channeled downstream to the core gas turbine engine wherein the airflow is further compressed. The compressed airflow is then channeled into a combustor, mixed with fuel, and ignited to generate hot combustion gases. The combustion gases are then channeled to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight. The other portion of the airflow discharged from the fan assembly exits the engine through a fan stream nozzle.
To facilitate channeling the airflow from the fan assembly to the fan stream exhaust, at least one known gas turbine engine assembly includes an outlet guide vane assembly that is used to remove swirl before the fan nozzle. Such an outlet guide vane assembly is configured to turn the airflow discharged from the fan assembly to a substantially axial direction prior to the fan flow being exhausted from the bypass duct. In addition to turning the fan airflow, the outlet guide vane assembly also provides structural stiffness to the fan frame. More specifically, outlet guide vane assemblies generally include a plurality of outlet guide vanes that are coupled to the fan frame.
In addition to outlet guide vanes, many fan frame assemblies include one or more (frequently two, diametrically opposed) dividing structures, often called “bifurcations”, which divide the annular space defined by the bypass duct into two semi-annular spaces. These dividing structures are typically hollow duct-like structures through which various mechanical, electrical, pneumatic, hydraulic, or other connections (including structural supports) can pass without causing disruption to the airflow through the bypass duct. The bifurcations “fair” or guide the flow in aerodynamic fashion around these structures, and may be integrated or blended into the profile of an upstream guide vane to reduce the number of individual airflow disruptions.
Geometric sweep and lean characteristics for guide vanes have been previously demonstrated to be useful design parameters for reducing noise caused by aerodynamic interactions between guide vanes and upstream and/or downstream rotating elements such as fan blades. However, since bifurcations are typically radially oriented there remains a need for an improved approach to integrating advanced design swept and/or leaned guide vanes with bypass duct bifurcations.